After a long day at work, there is nothing like a
good night's sleep! Just like on Earth, a worker in space goes to
bed at night then wakes up the next day and prepares for work all
over again. There are a few differences, though.

In space there is no up or down and there is no gravity.
As a result, astronauts are weightless and can sleep in any orientation.
However, they have to attach themselves to a wall, a seat or a bunk
bed inside the crew cabin so they don't float around and bump into
something.

Click an image to see how astronauts sleep.

Space shuttle and space station crews usually sleep
in sleeping bags. On the space shuttle, astronauts can also sleep
in the commander's seat, the pilot's seat or in bunk beds. There
are only four bunk beds in the space shuttle. So that means on missions
with five or more astronauts, the other crewmembers have to sleep
in a sleeping bag attached to their seats or to a wall.

On the space station there are two small crew cabins.
Each one is just big enough for one person. Inside both crew cabins
is a sleeping bag and a large window to look out in space. Currently,
space station crews have three astronauts living and working in
space for months at a time. Where does the third astronaut sleep?
If it's okay with the commander, the astronaut can sleep anywhere
in the space station so long as they attach themselves to something.

Astronaut Susan Helms slept in the huge Destiny Laboratory
Module by herself while she was living aboard the International
Space Station. This is on the opposite side of the station from
the Service Module where her crewmates slept. The length of the
International Space Station during that mission was 52 meters (171
feet) long.

Generally, astronauts are scheduled for eight hours of sleep at the end of
each mission day. Like on Earth, though, they may wake up in the
middle of their sleep period to use the toilet, or stay up late
and look out the window. During their sleep period, astronauts have
reported having dreams and nightmares. Some have even reported snoring
in space!

The excitement of being in space and motion sickness
can disrupt an astronaut's sleep pattern. Sleeping in close quarters
can also be disruptive since crewmembers can easily hear each other.
Sleeping in the shuttle's cockpit can also be difficult since the
Sun rises every 90 minutes during a mission. The sunlight and warmth
entering the cockpit window is enough to disturb a sleeper who is
not wearing a sleep mask.

When it is time to wake up, the Mission Control Center
in Houston, Texas, sends wake up music to the crew. Usually, Mission
Control will pick a song for a different astronaut each day. Sometimes
a family member will request a favorite song for their particular
loved one. Depending on the astronaut, Mission Control will play
all types of music such as rock and roll, country and western, classical,
or Russian music. However, only a shuttle crew receives wake up
music while a space station crew uses an alarm clock.